Reasons for Designation
Limestone or chalk has been the basic ingredient for lime mortar from at
least Roman times. Since the medieval period, lime has also been used as
agricultural fertiliser and, since the early 19th century, widely used in
a variety of other industries: as a flux in blast furnaces, in the
production of gas and oil, and in the chemical, pharmaceutical and food
industries.
The lime industry is defined as the processes of preparing and producing
lime by burning and slaking. The basic raw material for producing lime is
limestone or chalk: when burnt at high temperature (roasted or calcined),
these rocks release carbon dioxide, leaving `quicklime' which, by chemical
reaction when mixed with water (`slaking'), can be turned into a stable
powder - lime. Lime burning sites varied in scale from individual small
lime kilns adjacent to a quarry, to large-scale works designed to operate
commercially for an extended market and often associated with long
distance water or rail transport. Lime burning as an industry displays
well-developed regional characteristics, borne out by the regional styles
of East Anglia, West Gloucestershire or Derbyshire.
The form of kilns used for lime burning evolved throughout the history of
the industry, from small intermittent clamp and flare kilns, to large
continuously fired draw kilns that could satisfy increased demand from
urban development, industrial growth and agricultural improvement.
Small-scale rural lime production continued in the later 19th and 20th
centuries, but this period of the industry is mainly characterised by
large-scale production and the transfer of technologies from the cement
and other industries. The demand for mortars grew steadily during the 19th
and 20th centuries. The successful production of mortars made with
artificial cement represented an economic challenge to lime production and
gradually replaced the use of lime mortars in major construction and
engineering projects.
From a highly selective sample made at national level, around 200 lime
industry sites have been defined as being of national importance. These
have been defined to represent the industry's chronological depth,
technological breadth and regional diversity.
The remains of the lime kiln and associated quarries 330m west of Toft
Gate Farm survive extremely well. The kiln itself is a very rare design
and demonstrates clearly the method of its working. In addition, the
earlier prospecting pits retain important information about the wider lime
and lead industry in the area. Taken as a whole the monument is important
for understanding changes and developments in the 19th century commercial
lime industry.
Details
The monument includes standing, buried and earthwork remains of a 19th
century lime kiln, flue, chimney and associated quarries. Also included
are remains of earlier quarries and prospecting pits and workings for both
limestone and lead. The monument is located on the eastern flank of
Greenhow Hill, 330m west of Toft Gate Farm. The majority of the monument
lies within an enclosure fenced for public presentation of the kiln
complex.
There has been widespread extraction and processing of lime in the area
since medieval times when it was used for improving soil, for the
manufacture of mortar and plaster and as a building material. The late
18th and 19th centuries saw an increase in demand for lime and
technological advances were made to create large scale commercial kilns.
Little is currently known about the history, ownership and management of
the Toft Gate kiln. It is known that the Ingleby family held limestone
rights in the area from the early 17th century and lead mining rights from
1785. Maps dating from the 19th century to the present day show extensive
quarrying, shafts and at least two other lime kilns on the hillside.
Analysis of population records of local settlements has identified a
number of individuals in the area who were connected with the lime
industry although as yet none of these can be linked directly to the Toft
Gate kiln.
The kiln complex does not appear on the first edition Ordnance Survey (OS)
map of 1854. The map does however show parts of the area of the monument
being occupied by quarry workings, some remains of which can still be
identified. An enclosure map of 1867 also fails to depict the kiln but it
does refer to the existing quarry workings as a public quarry. By 1895 the
lime kiln appears on the OS map although the detail is unclear.
From map evidence and the development of lime production technology
elsewhere the kiln has been dated to the late 1860s. By 1909 the OS map
shows the complex in detail and includes features such as the kiln, flue,
chimney and quarries. It has been reported that the last wagon load of
lime left the site in the first few years of the 20th century. The Toft
Gate kiln was a continuous burn, dual feed, vertical furnace kiln. This
allowed for continuous production of lime. The flue and chimney improved
efficiency and vented fumes. It appears to have been an experimental
design as no similar examples of this style dating to this period are
known elsewhere. Some elements of the design can be found at other lime
kilns such as the Hoffman kiln at Ingleton and also at lead smelting sites
of which there were many local examples. The kiln was a tall, square stone
built structure with a central circular shaft. Crushed limestone was fed
into the top of the shaft and the fuel, most likely coal, was passed into
the shaft lower down to create a burn zone or firing level in the
mid-section of the shaft. The resultant burnt lime and coal ash was then
extracted from the bottom of the kiln.
The kiln survives almost completely. It was built in the western side of a
deep pre-existing quarry pit so that the lower parts of the south western
and north western sides of the kiln were built against bedrock and the
other two sides were free standing. The top of the kiln is approximately
at the same level as the top of the quarry face. The kiln was built of a
mixture of sandstone and limestone blocks, many of which are held in place
by iron ties.
The quarry has been used to tip material throughout the 20th century with
the result that the lower part of the kiln has been buried, thus obscuring
much of its base. The south east face is however partly exposed and the
top of two arched openings 1.5m wide are visible. These are the draw
holes, which allowed access to the base of the kiln to remove the lime.
The current ground level corresponds to the firing level, some 3.5m above
the bottom of the kiln. The kiln is exposed on all sides at this level and
it measures 5.9 sq m. At the firing level there are two openings on each
side an average of 1.3m wide and 1.5m high at the exterior and 0.3m wide
and 0.5m high on the inside. These led to chutes through which fuel was
fed into the kiln shaft. On the south western and north western sides
access to the fireboxes was from the contemporary ground level of the
quarry face. Access on the other sides appears to have been from a
platform supported by a stone plinth and timbers held in putlog holes,
which can be identified around the kiln sides. The top of the kiln is 5.5m
above current ground level although it is not clear whether this was the
original height. On the top of the kiln there is the circular shaft
opening measuring 2m in diameter. The shaft is 6.9m deep and widens
towards the bottom where it measures 2.7m in diameter. At the base of the
shaft the kiln takes the form of a barrel vaulted chamber aligned north
east to south west and measuring 5m by 3.8m.
On the south western side of the kiln there is a semi-circular arch the
same width as the kiln with a span of 2m which connects the kiln to the
ground. On the top of this arch there are eight bolts forming two squares
which are interpreted as the mountings for a crane which hoisted limestone
and fuel up to the kiln and possibly processed lime away. Processed lime
was transported by cart along the Grassington to Pateley Bridge road which
lies immediately to the north of the monument.
Fumes from the kiln were vented through the shaft top to a stone built
flue at the south west side of the arch and carried along the flue to a
chimney to the south west. The manner by which fumes were fed to the flue
from the shaft top is currently unknown. The flue survives virtually
complete for its entire length. It comprises a stone built tunnel 70m in
length with a rectangular profile measuring 0.8m wide and 1.4m high. The
top is made up of massive limestone blocks up to 0.3m thick and 1m long.
In places the flue stands on a plinth up to 4m wide, which was built to
carry the flue over uneven ground, formed in part by the earlier
quarrying.
The chimney is square in plan measuring 3.6m. Similar to the kiln, its
fabric is composed of a mixture of limestone and sandstone. It stands to a
height of 4.5m although it is not clear whether this was the original
height.
To the south of the kiln are the ruins of a stone structure built on top
of exposed bedrock approximately at the same level as the firing level.
The structure measures 12m north to south and 3m east to west. The west
wall survives as a revetment against the quarry face some 4m high. The
eastern side of the structure appears to have been open. The structure is
interpreted as a pair of bunkers possibly for storage of coal. Outside
the fenced area, 60m to the south of the chimney, at NGR SE12976428 there
is a sub-circular pond measuring 13m across. This was used as a reservoir
to provide water to the kiln. The water was fed to the kiln through a cast
iron pipe, sections of which are exposed above ground and it is considered
that the remainder still survives below ground.
The limestone used in the kiln was principally extracted from a large
quarry situated immediately to the north east of the kiln. The quarry is
rectangular in plan and measures 24m north to south by 22m east to west.
The northern and eastern faces are near vertical and stand 7m in height.
The eastern side has been obscured by later tipped material. Within the
quarry there are distinct working platforms from which the limestone was
hewn. Additional smaller quarries in the north east of the monument also
provided lime for the kiln. These survive as three clear quarry scoops up
to 40m by 18m in plan and 2.4m in depth. Working platforms also survive at
these quarries. The quarry was worked by blasting the exposed rock face.
There is no evidence of drilling so powder was probably inserted into
natural crevices in the quarry face. The explosives used for the blasting
were stored in powder houses, the location of these is not known.
Access to the kiln was on the north eastern side via a track way from the
Grassington to Pateley Bridge road. This track led to the quarry and kiln
although its termination has been obscured by later tipped material.
There is a level area 8m wide to the south of the kiln which is thought to
be a loading and turning area for carts.
The remains of the earlier limestone and lead extraction features are
located in the western and northern parts of the monument. The south
eastern part of the face of the earlier limestone quarry depicted on the
1854 map partly underlies the flue in the western part of the monument.
The steeply sloping quarry face some 2.5m high is clearly identifiable. In
the northern part of the monument and to the south of the chimney and flue
are remains of earlier prospecting pits. These survive as circular and
sub-circular earthworks up to 6m in diameter. Some of these features have
been truncated by later quarrying but remnants still survive on spurs of
unexcavated ground within the quarries. Some of these are interpreted as
prospecting pits and workings for lead. The date of the lead excavations
is probably mid to late 18th century although they could be as late as the
19th century if the lead vein was exposed in the course of limestone
quarrying. Further remains of the lead workings may be obscured by the
later lime kiln operations.
All fences, signs and gates are excluded from the scheduling, although the
ground beneath these features is included.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
